The instant invention relates to stackers for printed items (xe2x80x9csignaturesxe2x80x9d) after such signatures have exited a press and/or folder.
The flow of printed items in the modern print shop includes many items of equipment. These items serve to, automate the printing process as well as to provide uniformity to the printed items. To allow of the creation of many advertising items and the like, the modern print shop must not only print the items but also fold and stack the printed items with great uniformity and speed.
The instant invention relates to improvements in the technology of signature stackers which receive printed items from an article folder which folds printed items received from a press. These stackers, which comprise the final step in the process of assembly of many printed items have, in the past, been the cause of damage to the printed items. This damage includes crushing the printed items, folding over of the edges of such items or creasing the items. Additionally, previous stackers have required complicated direct current drive systems as well as chain and sprocket assemblies to achieve the speed control required by this particular piece of equipment. These drive assemblies have been the source of problems relating to oil sling onto the printed items from the chain as well as the additional requirement of providing a direct current supply to the drive motor.
The instant invention in the presently preferred embodiment thereof operates to receive signatures, arranged imbricate, from a press and stack same into a substantially vertical stack. This is accomplished by means of a feed belt in cooperation with the drive drum wherein the drum is of such radius as to permit the signatures to be carried about the periphery thereof without the signatures having suffered such curvature that the signatures are unable to recover their previously planar configuration; that is to say that the maximum curvature for elastic recovery of the signatures is not exceeded. Additionally, the invention comprehends a direct drive system, wherein the drum is driven and supported by shafting which is connected by gearing directly to the drive motor; thereby obviating the need for chains and the problems associated therewith as mentioned previously.
It is therefore a primary object of the invention to provide for a drive drum having a curvature less than the maximum elastic recovery curvature of a signature;
It is another object of the invention to provide for a direct drive system which precludes the possibility of oil contamination of the signatures;
It is a further object of the invention to provide for an alternating current drive motor for such direct drive system.
These and other objects of the instant invention shall become apparent from the Detailed Description of the Preferred Embodiment and Claims directed thereto.